Telemetry and Location for Long-Duration Balloon Flights

Abstract

Small 3-meter diameter balloons have flown for as long as 744 days, circling the globe 50 times. The balloons carried instrument packages weighing only 200 grams. These light systems require simple low power telemetry location techniques. HF telemetry and sun angle location were used on the original flights. More recently, polar orbiting satellites have collected telemetry and located the balloons. These satellites carry a location system called ARGOS, which locates by measuring the doppler shift in frequency as the satellite overflies the balloon. The doppler location technique requires an ultra-stable balloon transmitter frequency. A new polar-orbiting satellite location system promises an even greater reduction in balloon electronic complexity. This system locates using an interferometer to measure the direction from which the signal arrives. No ultra-stable transmitter is required. At the opposite end of the balloon spectrum are large 20-meter diameter superpressure balloons carrying 250 kg payloads containing complicated experiments. These balloons can theoretically fly for 20 years and will have solar powered propulsion systems that will move them in latitude. The balloon systems will require onboard navigation, high data rate telemetry, and command reception capability. A network of geostationary satellites is needed to provide the required telemetry link. Future location systems should combine orbiting and geostationary satellites to provide accurate global location and real-time data collection.